Prostate-specific membrane antigen expression in normal and malignant human tissues

An extensive immunohistochemical analysis was performed on a panel of well-characterised normal and malignant human tissues to define the pattern of prostate-specific membrane antigen expression. Detectable levels were identified in prostatic epithelium, duodenal mucosa and a subset of proximal renal tubules, and a subpopulation of neuroendocrine cells in the colonic crypts also showed immunoreactivity; all other normal tissues, including cerebral cortex and cerebellum, had undetectable levels. Thirty-three of 35 primary prostate adenocarcinomas and 7 of 8 lymph node metastases showed tumour cell staining, while 8 of 18 prostate tumours metastatic to bone expressed it. All other non-prostatic primary tumours studied had undetectable levels, but intense staining was seen in capillary endothelial cells in peritumoral and endotumoral areas of certain malignancies, including 8 of 17 renal cell carcinomas, 7 of 13 transitional cell carcinomas and 3 of 19 colon carcinomas. The decrease in immunoreactivity in advanced prostate cancer suggested that expression is linked to the degree of tumour differentiation.